Cardiac Arrhythmias are abnormal heart rhythms that can cause the heart to pump blood less effectively. Atrial fibrillation (AF) is one of the most common heart arrhythmia conditions. AF causes the left atrium to beat irregularly and reduces the efficiency of the “atrial kick” that helps to move blood into the left ventricle. The left atrial appendage (LAA) is a muscular pouch located high on the free wall of the left atrium. The anatomy of the LAA is such that blood has a tendency to stagnate and form clots within the LAA. As blood flow is reduced with the progression of AF, the potential for clot formation increases tremendously. Clots formed in the LAA can embolize into the bloodstream and move into the brain, where they can become lodged and eventually lead to stroke.
Existing techniques to prevent flow stagnation in the LAA include occlusion of the LAA as in U.S. Pat. No. 6,730,108 to Van Tassel, remodeling or dilation of the LAA to increase blood flow as in U.S. Patent Application Publication No. 2005/0234540 A1 (Peavey et al.), and piercing the LAA for placement of conduits to increase blood flow as in U.S. Pat. No. 8,019,404 to Kapadia and U.S. Patent Application Publication No. 2012/0022427 A1 (Kapadia). Occluding the LAA is undesirable for a variety of reasons, for example, because the LAA is a source of important hormones, and because the geometry of the LAA varies from person to person, making occlusion of the oval-shaped ostium with an implant difficult. Also, known occlusion devices typically are mounted or secured to tissue surrounding the LAA. Since the tissue surrounding the LAA is relatively thin, implanting such an occlusion device can increase the risk of rupture and pericardial effusion. Additionally, it is believed that the LAA acts as a compliance chamber and helps to regulate blood pressure in the left atrium. Hence, it is desirable to maintain the flow of blood through the LAA.
Similarly, simply remodeling or dilating the LAA in cases of AF is ineffective in preventing flow stagnation because the lack of atrial contraction still limits the amount of blood flowing through the LAA. Accordingly, improvements to devices and methods for increasing flow through the LAA are desirable.